969
FXPQ50 PGUM 061948
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
548 AM CHST FRI AUG 7 2026
MARIANAS UPDATE
A MONSOON-DRIVEN SQUALL LINE IS EXPECTED TO BRING HEAVY SHOWERS AND
THUNDERSTORMS, ALONG WITH GUSTIER WINDS, TO TINIAN AND SAIPAN TODAY.
LEFTOVER STRATIFORM FROM NEARBY CONVECTION IS LIKELY TO BRING ON-
AND-OFF SHOWERS TO ROTA AND GUAM, ALBEIT LESSER IN COVERAGE. AFTER, A
WETTER PERIOD IS EXPECTED TO CONTINUE ACROSS THE MARIANAS FOR MUCH OF
THE FORECAST PERIOD, AS ANOTHER PULSE IN THE MONSOON SURGE INDUCED
BY VARIOUS DISTURBANCES ANCHORING WITHIN THE MONSOON TROUGH.
COMBINED SEAS OF 9 TO 11 FEET ARE EXPECTED TO GROW ANOTHER FOOT BY
EARLY NEXT WEEK, REMAINING HAZARDOUS TO SMALL CRAFT THROUGH AT LEAST
THE FIRST HALF OF NEXT WEEK.
EASTERN MICRONESIA UPDATE
LITTLE CHANGE WAS MADE TO THE FORECAST. A TROPICAL RIDGE WILL REMAIN
PINNED BETWEEN THE EQUATOR AND THE MAIN ISLANDS OF MICRONESIA, AS
MOST OF THE CONVECTION STAYS CLEAR OF THE AREA WELL TO THE NORTH.
THIS WILL ALLOW A DRY SPELL TO CONTINUE ACROSS MUCH OF EASTERN
MICRONESIA. HOWEVER, A PROXIMITY TO A DEVELOPING DISTURBANCE NEAR THE
DATE LINE IS LIKELY TO BRING LOW-END SCATTERED SHOWERS TO MAJURO
IN THE AFTERNOON.
WESTERN MICRONESIA UPDATE
NO CHANGES WERE MADE TO THE FORECAST. THE AFOREMENTIONED TROPICAL
RIDGE WILL CONTINUE TO PRODUCE A DRIER REGIME ACROSS MUCH OF WESTERN
MICRONESIA AS WELL, WITH PERIODS OF MOSTLY CLEAR NIGHTS POSSIBLE,
ESPECIALLY AT PALAU. LONG-PERIOD SWELL, ORIGINATING FROM DISTANT
TYPHOON DOLPHIN NEAR OKINAWA, IS STILL EXPECTED TO BRING HAZARDOUS
SURF ALONG NORTH-FACING REEFS THROUGH MUCH OF THE WEEKEND. AS SWELLS
DIMINISH, SURF IS EXPECTED TO SUBSIDE BELOW HAZARDOUS LEVELS OF 9
FEET BY SUNDAY NIGHT.
PREV DISCUSSION
/ISSUED 642 PM CHST THU AUG 6 2026/
MARIANAS SYNOPSIS...
SATELLITE AND RADAR OBSERVATIONS SHOW SCATTERED SHOWERS NEAR THE
ISLANDS AND NUMEROUS SHOWERS OVER THE COASTAL WATERS OF THE MARIANAS.
ALTIMETRY AND BUOY DATA SHOW COMBINED SEAS BETWEEN 8 TO 11 FEET.
DISCUSSION...
NUMEROUS HEAVY SHOWERS AND ISOLATED THUNDERSTORMS MOVED ACROSS GUAM
THROUGH MUCH OF THE DAY TODAY. SOME 2 TO 4 INCHES OF RAIN WERE
REPORTED BY RAIN GAUGES AND REPORTS FROM OBSERVERS. THE AFTERNOON
RAINFALL TOTAL AT WFO GUAM WAS 2.35 INCHES. ADDITIONAL SHOWERS AND
THUNDERSTORMS ARE EXPECTED TONIGHT, WHICH COULD LEAD TO FLOODING
CONCERNS, ESPECIALLY ACROSS SOUTHERN GUAM. SHOWER COVERAGE LOOKS TO
DECREASE FRIDAY THROUGH SUNDAY AS THE SOUTHERN END OF THE MONSOON
DECREASES IN SHOWER ACTIVITY. AS THE PATTERN DRIES OUT, BREEZY
CONDITIONS WILL RETURN THIS WEEKEND.
UNCERTAINTY REMAINS HIGH IN THE EVOLUTION OF THE BROADER PATTERN
NEXT WEEK AS SEVERAL DISTURBANCES LOOK TO INTERACT WITH THE MONSOON
TROUGH. MODEL GUIDANCE IS IN A RELATIVELY GOOD AGREEMENT THAT THERE
WILL BE A FEW DISTURBANCES RACING EASTWARD NORTH OF THE CNMI NEXT
WEEK, HOWEVER MODELS VARY GREATLY ON BOTH LOCATION AND INTENSITY.
SOME GUIDANCE BRING A COUPLE OF DISTURBANCES FURTHER SOUTH INTO THE
FAR NORTHERN MARIANAS ISLANDS. THIS SCENARIO SHIFTS THE MONSOON
SURGE SOUTH OVER THE CNMI AND GUAM, LEADING TO HIGHER IMPACTS FROM
WIND AND RAIN NEXT WEEK. OTHER GUIDANCE SHOWS THE DISTURBANCES
EITHER MOVING FURTHER NORTH, OR BECOMING MORE ORGANIZED. THIS
SCENARIO SHIFTS THE STRONGEST WINDS AND RAIN NORTH OF CNMI AND GUAM.
OVERALL, DIRECT IMPACTS FROM THESE DISTURBANCES ARE NOT EXPECTED FOR
THE CNMI AND GUAM, BUT THE INFLUENCE ON THE MONSOON SURGE WILL
GREATLY DEPEND ON WHERE THE DISTURBANCES TRACK AND HOW STRONG THEY
BECOME. IF TRENDS SHIFT THE MONSOON SURGE SOUTHWARD NEXT WEEK, THEN
HYDROLOGICAL PRODUCTS MAY BE NEEDED FOR THE MARIANAS NEXT WEEK.
MARINE...
COMBINED SEAS REMAIN BETWEEN 8 AND 11 FEET AND ARE EXPECTED TO
REMAIN WITHIN THAT RANGE THROUGH TONIGHT. A SLIGHT DECREASE IN SEAS
IS EXPECTED FRIDAY BEFORE ANOTHER INCREASE THIS WEEKEND. THE SMALL
CRAFT ADVISORY IS NOW IN EFFECT UNTIL MONDAY MORNING. POUNDING SURF
OF 10 TO 12 FEET WILL CONTINUE THROUGH THE WEEKEND ALONG WEST AND
NORTH FACING REEFS. THE HIGH SURF ADVISORY AND HIGH RISK OF RIP
CURRENTS WAS EXTENDED UNTIL MONDAY AFTERNOON. THESE MARINE HAZARDS
COULD CONTINUE INTO NEXT WEEK AS THE MONSOON PATTERN INTENSIFIES OVER
THE REGION.
TROPICAL SYSTEMS...
INVEST 96W IS LOCATED ALONG THE EDGE OF GUAM'S AOR (AREA OF
RESPONSIBILITY), CENTERED NEAR 26N164E. THE JOINT TYPHOON WARNING
CENTER (JTWC) RATES 96W AS "MEDIUM" FOR DEVELOPMENT, MEANING IT WILL
LIKELY DEVELOP INTO A SIGNIFICANT TROPICAL CYCLONE, BUT NOT WITHIN
THE NEXT 24 HOURS. ASCAT WINDS FROM THIS MORNING DEPICT A MUCH
HEALTHIER LOW-LEVEL CIRCULATION COMPARED TO YESTERDAY EVENING, BUT
STILL BROAD AND ASYMMETRICAL. 25 TO 35 KNOT WINDS ARE SEEN THROUGHOUT
96W'S WESTERN TO NORTHEASTERN FLANKS, EXTENDING OUTWARD 400 MILES
NORTH OF THE CENTER, WITH SOME SMALLER AREAS EXCEEDING 40 KNOTS. WIND
SPEEDS ARE LOWER SOUTH OF THE DISTURBANCE, AROUND 10 TO 20 KNOTS
WITHIN THE SOUTHEASTERN TO SOUTHWESTERN FLANKS. SATELLITE IMAGERY
SHOWS A BROAD AREA OF DEEP, FLARING CONVECTION WRAPPING INTO THE
CENTER WITH THE TAIL EXTENDING FAR TO THE SOUTH NEAR WAKE ISLAND.
MODEL GUIDANCE KEEPS 96W ALONG A GENERALLY NORTHWEST TRACK AS IT
CONTINUES TO EXIT THE REGION.
FOR MORE INFORMATION ON INVEST 96W, PLEASE REFER TO BULLETINS FROM
THE JOINT TYPHOON WARNING CENTER UNDER WMO HEADER ABPQ10 PGTW.
EASTERN MICRONESIA...
NOT MUCH HAS CHANGED AS THE MONSOON TROUGH REMAINS NORTH OF THE
REGION, MAINTAINING A WEST TO SOUTHWEST FLOW. THE BEST CONVERGENCE
AND MOISTURE IS NORTH OF THE REGION AS IT WRAPS INTO INVEST 96W NORTH
OF WAKE ISLAND, WITH JUST LIGHT TO GENTLE WINDS PREVALENT ACROSS THE
REGION. AS SUCH, ONLY ISOLATED SHOWERS AND PERHAPS A THUNDERSTORM CAN
BE EXPECTED THROUGH NEXT WEEK.
AS FOR MARINE CONDITIONS, ALTIMETRY SHOWED SEA HEIGHTS OF 7 TO 8 FEET
NEAR POHNPEI, WITH LOWER HEIGHTS SOUTH AND EAST. BOTH WAVE WATCH III
AND GFS GLOBAL WAVE SHOW SURF WILL REMAIN LOW ENOUGH TO PRECLUDING
ANY HEADLINE NECESSITY, AS BOTH MODELS INDICATE 4 TO 5 FOOT SWELL AT
13 SECONDS, WELL SHORT OF CRITERIA FOR ANY HIGH SURF ADVISORY. SEAS
LOOK TO DROP A FOOT OR SO THROUGH THE WEEKEND, WITH LIGHT TO GENTLE
WINDS PREVAILING.
WESTERN MICRONESIA...
A DRIER PATTERN PERSISTS WELL SOUTH OF THE MONSOON SURGE. A BAND OF
DEEP CONVECTION HAS BEEN FOCUSED OVER GUAM, ORIENTED FROM NORTHWEST
TO SOUTHEAST, AND SWATHS OF UPPER-LEVEL CLOUD DEBRIS ARE STREAMING
SOUTHWARD ACROSS THE OUTER ISLANDS OF YAP AND OVER NORTHERN CHUUK
STATE. OUTFLOW BOUNDARIES ASSOCIATED WITH PRIOR CONVECTION ARE
SWEEPING JUST NORTH OF WENO AND COULD PRODUCE BRIEF MODERATE SHOWERS
OR EVEN A THUNDERSTORM OR TWO THIS EVENING OVER ITS COASTAL WATERS.
OVER PALAU AND YAP, PARTLY CLOUDY SKIES PREVAIL, WITH LIGHT, ISOLATED
SHOWER BANDS AND ROUGHLY 10 TO 20 KNOT WINDS ACROSS THE REGION. A
SIMILAR PATTERN WILL PREVAIL THROUGH THE WEEKEND AND MUCH OF THE
COMING WEEK, AS THE MONSOON TROUGH, AND ASSOCIATED MONSOON SURGE,
REMAIN WELL NORTH OF THE REGION.
ALTIMETRY AND YAP BUOY DATA DEPICT COMBINED SEAS BETWEEN 6 AND 8
FEET AT YAP AND 5 TO 7 FEET NEAR PALAU AND CHUUK. A LONG-PERIOD NORTH
SWELL IS ARRIVING AT YAP, EMANATING FROM DISTANT TYPHOON DOLPHIN,
WHICH IS EXPECTED TO GENERATE HAZARDOUS SURF ALONG NORTH FACING REEFS
THROUGH MUCH OF THE WEEKEND, AND A HIGH SURF ADVISORY IS NOW IN
EFFECT FOR YAP UNTIL 5 PM CHST SUNDAY. SURF IS FORECAST TO BUILD TO
10 TO 11 FEET ALONG NORTH-FACING REEFS OF YAP, AND UP TO 8 FEET ALONG
NORTH-FACING REEFS OF PALAU, REACHING NEAR-HAZARDOUS LEVELS FOR
PALAU OVER THE NEXT DAY OR SO AS WELL. MEANWHILE, SLIGHTLY ELEVATED
SURF CONTINUES ALONG WEST-FACING REEFS OF PALAU AND YAP DUE TO A
PERSISTENT WEST TO SOUTHWEST MONSOON SWELL, BUT IS EXPECTED TO REMAIN
BELOW HAZARDOUS LEVELS.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST MONDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST MONDAY FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM CHST MONDAY FOR PMZ151>154.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: MONTVILA
MARIANAS: WILLIAMS EAST MICRONESIA: DOLL
WEST MICRONESIA/TROPICAL: DECOU
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